Novel .ALPHA.-Pyrones Produced by a Marine Pseudomonas sp. F92S91: Taxonomy and Biological Activities
Bibliographic record
Abstract
Inhibitors of the enzymes involved in fatty acid biosynthesis (FAB) have been reported as antibacterial agents. These include thiolactomycin, cerulenin, triclosan, diazoborine, naphthyridinones, aminopyridines and pyridoindoles. Our search for new FAB inhibitors, using a lacZ reporter cell-based screen, led to several confirmed hits. Culture F92S91, later identified as a Pseudomonas sp. based on 16S profiling, was found to produce two alpha-pyrones (I and II) and three high molecular weight peptides. The pyrones were unstable under acidic conditions, and they were rearranged into a furanone derivative (III). Of these compounds, pyrone I was the most active with MICs (microg/ml) against B. subtilis (1 to approximately 2), MRSA (2 to approximately 4), M. catarrhalis (4) and VRE (2 to approximately 64). Effects on macromolecular synthesis and membrane functions were tested in B. subtilis. Pyrone I nonspecifically inhibited incorporation of radiolabeled precursors into DNA, RNA and protein within 5 minutes of drug exposure, similar to that of triclosan. Both compounds also inhibited the cellular uptake of these precursors. Cerulenin did not have an effect until 30 minutes of drug treatment. Pyrone I and triclosan were membrane-active (BacLight test); however, pyrone I (at < or = 128 microg/ml concentration) was not hemolytic to human RBCs in contrast to triclosan, which was hemolytic at 16 microg/ml. These data suggest that pyrone-I, unlike triclosan, selectively affects bacterial membrane function.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".